I have to find how many numbers in the following String,
'~1~~2~~123~~~~12~~1~~~~' and the output should be 5.
Any help?
MySQL cannot do that directly. You would have to dig into UDF (User defined functions). It would allow you to create a function that returns the number of number substrings in a string.
Regular expression need pattern to match and there no pattern to use regular expression in provided example. You can go here to see regular expression in mysql.
Related
I try get name of city's from string '{"travelzoo_hotel_name":"Graduate Minneapolis","travelzoo_hotel_id":"223","city":"Minneapolis","country":"USA","sales_manager":"Stephen Conti"}'
I try this regexp:
SELECT REGEXP_SUBSTR('{\"travelzoo_hotel_name\":\"Graduate Minneapolis\",\"travelzoo_hotel_id\":\"223\",\"city\":\"Minneapolis\",\"country\":\"USA\",\"sales_manager\":\"Stephen Conti\"}'
,'(?:.city...)([[:alnum:]]+)');
I have: '"city":"Minneapolis'
Me need only name of city:Minneapolis.
How to use groups in queries?
My example in regex101
Help me Please
I assume you are using MySQL 8.x that uses ICU regex expressions.
It looks like the string you want to process is JSON. You may use JSON_EXTRACT with JSON_UNQUOTE and a '$.city' as JSON path then:
JSON_UNQUOTE(JSON_EXTRACT('{"travelzoo_hotel_name":"Graduate Minneapolis","travelzoo_hotel_id":"223","city":"Minneapolis","country":"USA","sales_manager":"Stephen Conti"}', '$.city'))
will return Minneapolis.
In your regex, the non-capturing group pattern is still matched and appended to the match value. "Non-capturing" only means no separate memory buffer is alotted to the text captured with a grouping construct. So, you may fix it with '(?<="city":")[^"]+' pattern where (?<="city":") is a positive lookbehind that matches "city":" but does not put it into the match value. The only text you will have in the output is the one matched with [^"]+, 1+ chars other than ".
I have a table with tens of thousands of VIN numbers. Many of them look along the lines of this:
6MMTL#A423T######
WVWZZZ3BZ1?######
MPATFS27H??######
SCA2D680?7UH#####
SAJAC871?68H06###
The # represents a digit and the ? a letter (A-Z).
I want to search for the following: 6MMTL8A423T000000.
I am struggling to work out the logic. Should I use a function? Should I use mysql regex?
A regular expression match would be a good way to approach this problem. What you need to do is convert the vin expressions into valid regular expressions that represent the logic you've indicated. Here's a simple way to do that:
replace(replace(vin,'#','[0-9]'),'?','[A-Z]')
This would convert 6MMTL#A423T###### into 6MMTL[0-9]A423T[0-9][0-9][0-9][0-9][0-9][0-9]. Now using this converted format, do a regular expression match query:
select vin
from vins
where '6MMTL8A423T000000' regexp replace(replace(vin,'#','[0-9]'),'?','[A-Z]')
Sample Output: 6MMTL#A423T######
Demo: http://www.sqlfiddle.com/#!2/ee4de/4
I need a PHP regular expression that will compare stings similar to mysql Match Against behaviour.
e.g:
string = "findmatches";
$pattern = 'fildcatches';
this pattern is supposed to match the string
Thanks a lot
Regular expression may not be the best solution for your needs, try instead the PHP construct similar_text() :
http://php.net/manual/en/function.similar-text.php
The function returns the similarity between two strings in percentage and the number of matching chars.
In field post_content I have a string like this in nearly 800 rows:
http://somesite.com/">This is some site</a>
I need to remove everything from "> onwards so that it leaves just the URL. I can't do a straight find and replace because the text is unique.
Any clues? This is really my first foray into MySQL database modifications but I did do an extensive search before posting here.
Thanks,
~Kyle~
From this site: http://www.regular-expressions.info/mysql.html
LIB_MYSQLUDF_PREG
If you want more regular expression power in your database, you can consider using LIB_MYSQLUDF_PREG. This is an open source library of MySQL user functions that imports the PCRE library. LIB_MYSQLUDF_PREG is delivered in source code form only. To use it, you'll need to be able to compile it and install it into your MySQL server. Installing this library does not change MySQL's built-in regex support in any way. It merely makes the following additional functions available:
Here it comes...
PREG_CAPTURE extracts a regex match from a string. PREG_POSITION returns the position at which a regular expression matches a string. PREG_REPLACE performs a search-and-replace on a string. PREG_RLIKE tests whether a regex matches a string.
Sounds exactly what you're looking for.
All these functions take a regular expression as their first parameter. This regular expression must be formatted like a Perl regular expression operator. E.g. to test if regex matches the subject case insensitively, you'd use the MySQL code PREG_RLIKE('/regex/i', subject). This is similar to PHP's preg functions, which also require the extra // delimiters for regular expressions inside the PHP string.
See this post: How to do a regular expression replace in MySQL?
Either that or you could just write a script in any lanugage which goes through each record, does a regex replacement and then updates the field. For more info on regex, see here: http://www.regular-expressions.info/reference.html
There's a number of options. One might be to use SUBSTRING_INDEX():
UPDATE
table
SET field = SUBSTRING_INDEX( field, '">', 1 )
It's possible - there is a syntax for User Defined Functions which would let you pass in a regular expression pattern that matches the link and strips everything else.
However, this is quite complicated for somebody new to MySQL, and from your question, this sounds like a one-off. In which case - why not just use Excel and then reimport the data?
Great stuff!
All seems doable with a little bit of time and self education.
In the end, I exported that table as a CSV in Sequel Pro and did some nifty find and replace work in Coda. Not as sophisticated as your suggestions, but it worked.
Thanks again,
~Kyle~
Is it possible to get the (first?) match of a regex and output it within a select? It looks like the REGEXP function only return whether there has been a match or not. I want to be able to extract information out of a varchar column without having to use complex SUBSTRING-LOCATION nestings.
Any ideas?
http://dev.mysql.com/doc/refman/5.1/en/regexp.html that's all there is. You can't do more than pattern comparison.